JPS5919241A - Recording and reproducing device of optical information - Google Patents

Abstract

PURPOSE:To detect a dropout of an information recording region, by using the 1st clamping circuit which clamps the reproduced signal of an optical recording disk and the 2nd clamping circuit having the polarity opposite to the 1st clamping circuit. CONSTITUTION:A reproduced signal B is amplified by an amplifier 12 and then supplied to the 1st clamping circuit 13 as well as to the 2nd clamping circuit 16 through an inverse amplifier 15 of gain 1. The outputs C and D clamped by the circuits 13 and 16 respectively are binary-coded by the 1st and 2nd comparators 14 and 17 and with the threshold voltage G of a threshold voltage generating circuit 18. The binary-coded outputs E and F of the circuits 13 and 16 are supplied to a dropout counter circuit 21 in the form of a signal H from which the spurious signals produced at the circuits 13 and 16 are eliminated by a clamp compensating circuit 19. The length and the number of dropouts are accumulated and added together by a clock pulse K generated from a clock generating circuit 20. The output J of the circuit 21 is fetched to a controller to device a defective sector.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an optical information recording/reproducing device.

This invention relates to detecting dropouts when checking the quality of recording tracks and controlling information recording according to the results.

Conventional configuration and its problems Recording and reproducing signals at high density on an optical recording disk by concentrating the light of a laser etc. to a beam with a diameter of 1/1 m or less is a good method when recording signals on the master of a video disk. It's being done. Recently, with the development of new optical recording materials, optical recording and reproduction of digital signals and video signals on optical disks is being carried out. Furthermore, in order to record and reproduce high-density signals with a simple device, a disk having an optically detectable guide track is used to record and reproduce signals along or within the guide track. will be carried out. As an example of the above-mentioned guide track, it has been proposed that a groove with a width of 05 to 1 μm and approximately λ/8 of the wavelength of the light from the light source used for recording and reproduction is used. These grooves are arranged at appropriate track pitches over the entire signal recording area on the disk in a circular pattern, a v-shape, or concentric circles. As another example of the guide track, a servo track on which servo signals are recorded is formed in advance, and signals are recorded and reproduced along this servo track.

The present invention is directed to recording and reproducing digital data on and from an optically recordable and reproducible disc as described above. FIG. 1 shows an example of this optical recording disk. In order to simplify the drawing, FIG. 1 shows only one signal recording track. In FIG. 1, N indicates a unique address number recorded in advance to distinguish this track from other tracks. A certain track shows an area. "Lent...nm
indicates a sector address area in which a sector address signal unique to each sector is recorded for use by dividing one track into a large number of sectors. 4th!・-・tm is
It shows an information recording area in which necessary information signals are recorded and reproduced corresponding to each sector address. The arrow indicates the direction of rotation of Dinuk.

Various methods have been proposed to ensure recording quality when recording and reproducing, for example, a digital μ signal for each sector on such a disc. One of them is D RA W (Direct Read After).
There is a write method. In this method, for example, two light beams are prepared for recording and reproducing on a disk, and these two light beams are placed extremely close to each other on the same track (
For example, 5 to 10 voice doors are placed side by side, recording is performed with one light beam, and at the same time, the recorded signal is read out with the other light beam, and the recorded signal is instantaneously reproduced to check whether correct recording has been performed.

If there is an error in the reproduced signal, the same signal is recorded again in the next sector. The above-mentioned two light beams are often generated using two light sources with different wavelengths to prevent confusion between the recording light and the reproducing light. If recording and reproduction were performed using light of one wavelength, it would be difficult to separate the recording and reproduction light, and even if it were possible, the optical system would be complicated. Another method is to use two optical heads.
One possible method is to prepare one head for recording and check playback for the other head, but in this case, due to constraints on the physical size of the recording head and playback head, the recording light and playback light will be on the disk to a large extent. If the disc is placed far away (for example, the disc is 90° or 180° 141E), reading cannot be checked after recording, so you must wait for the disc rotation time between recording and checking, or wait for the next reading after an error is detected. There is a rotational wait time for the DINUK to write the same information in the same sector, and the average data transfer rate for the data recording sector is significantly slowed down. Furthermore, the average data transfer rate decreases as the number of sectors during one track rotation increases.

In addition, when performing a recording/reproduction check with one light, for example, when writing data to the information recording area t1 after confirming the sector address in Fig. 1, data is written to tl, and then when the disk rotates once, the data of tl is If there is an error after playing back and checking, the same data can be written to 4. In this case, the configuration is simpler than the above method of preparing two optical heads, but the average data transfer rate is further reduced. Furthermore, the greater the number of sectors during one track revolution, the lower the average data transfer rate will be.

Several methods for guaranteeing the quality of recorded content have been described above, but from another perspective, data must not be recorded twice in each sector of an optical recording disk. If this happens, the previously recorded data will be destroyed, causing a practical problem. Therefore, when recording data in a specific sector, it is necessary to check in advance that no signal is recorded in the sector. If such a function is included in the DRAW method, the average data transfer rate will further decrease.

OBJECTS OF THE INVENTION The present invention aims to provide a dropout inspection device that guarantees the quality of recording by inspecting each sector in advance and provides a device that can record and reproduce data without reducing the average data transfer rate. The purpose is to In particular, it accurately detects the number of dropouts in tracks where recorded sectors and unrecorded sectors coexist to ensure recording quality and prevent inadvertent reduction of the sector recording rate of optical recording disks. .

Structure of the Invention In order to achieve the above object, the present invention includes a first clamp circuit for combing a reproduction signal of an optical recording disk, and a second clamp circuit having a polarity opposite to that of the first clamp circuit.
Dropouts in the information recording area are detected by means for binarizing the outputs of the first and second clamp circuits at a predetermined threshold voltage and by means for counting the time width of the binarized outputs. It is something.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Second
The figure shows an outline of the configuration of an optical recording/reproducing device. (1) shows a light source of a semiconductor laser (LD display); (2) shows a condensing lens; (3) shows, for example, a beam amplifier; (4) shows a focusing lens; and (5) shows an aperture lens.

The aperture lens (5) focuses the light from the LD (1) onto the disk (8) into light having a diameter of about 1 μm. (6) is a photodetector (
PD) detects the reflected light from the disk (8) and converts it into an electrical signal. (7) indicates a disk motor, which rotates the disk (8) at a specified speed. Disc (8
) is, for example, the disk shown in the example of FIG. OQ is an LD drive circuit, which switches the optical output of the LD (1) according to recording or reproduction, or performs optical father adjustment using one sector worth of data. A recording signal is input to the terminal.

(11) is a preamplifier which amplifies the output of PD (6) and generates a reproduction signal at terminal e). The 0-degree part surrounded by the dotted line in FIG. 2 is hereinafter referred to as an optical head.

In the present invention, when a signal is recorded/reproduced in an arbitrary sector in the track of address number N in FIG. 1 by using the optical recording/reproducing apparatus shown in FIG. 2 on the disk shown in FIG. After searching and capturing track N, the track is irradiated with a reproduction light while the disk rotates once, and the quality of each sector is inspected and the presence or absence of a sector in which a signal has been recorded begins to be recorded, as well as the next data signal to be supplied. The present invention provides a device that attempts to detect the desired sector (search the beginning of recording).According to this method, the check of all sectors is completed in the first revolution of track N, and the check of all sectors is completed in the next revolution. Signals can be recorded in all sectors that satisfy the recording conditions of N. Therefore, the average data transfer rate during signal recording can be significantly faster than in some examples of the pre-check method.

Further, although the case where only one track is checked in advance has been described above, the same thing can be said even if the free track is checked over several revolutions of the disk.

Therefore, the number of tracks to be checked in advance may be determined depending on the length of data to be recorded at that time.

The present invention will be further explained in detail below with reference to the drawings. Third
The figure shows one +)4 example of the reproduced signal processing circuit. Second
The playback signal from the preamplifier (11) shown in the figure (however, the playback signal in this case is all the signals that are output as electrical signals regardless of whether the optical spot is irradiated on the recorded or unrecorded part of the disc. ) are supplied to a plurality of illustrated signal processing circuits.

The track address detection circuit (110) detects the signal of the address area N unique to each track on the disk shown in FIG. 1. Generally, the address signal of N is the information recording area t1.
t1...1rrFc The signal representing the sector address area n1snj...nm is recorded in a form different in frequency or code, and is separated from these by the track address signal. is detected and the control fluid @ (118
) through line (a). This address signal is used to detect a track to be recorded, a track to reproduce a signal, or a position where the optical head exists.

The sector address detection circuit (111) detects the address of the sector in the track captured by the optical head.
At that point, find the sector number where the light beam is running! (b) to the control device (118). That is, when the light beam is scanning the area t1, the sector address detection circuit (111) detects the sector address area n.
The control fluid is transmitted to the control fluid @ (118).

The sector section detection circuit (112) detects that the light beam is in the information recording area 1. ．． 1. ...This is a circuit that generates a signal only while scanning the image. That is, for example, in the t1 area of FIG. 1, a signal indicating the level ν is connected to the section from the trailing edge of the sector address area n1 to the leading edge of the sector address area n1 by a line (
c) occurs. This signal is used to check whether there is a recorded signal in the information recording area or whether there are dropouts or other defects. If the signal is to be recorded at I8, it is used as a gate signal to supply the recording signal to the semiconductor laser.

The dropout detection circuit (113) includes a preamplifier (1
1) Detect whether an impulsive dropout exists in the output. This detection is performed only while the output line (c) of the sector section detection circuit (112) is at a high level. That is, information recording area 1 in FIG. ．．
1□...It is carried out only during tm, and the track address area N
, sector address area rL1pnN...nm. The dropout inspection circuit (114) inspects the time width, number of dropout signals in one sector, speed of repetition, etc. of the dropout signal supplied to the line (d), and the error correction circuit (117) inspects the dropout signal supplied to the line (d). It is determined whether the dropout is an error-correctable dropout or an error-uncorrectable dropout according to predetermined criteria, and the result is transmitted to the control device through the line (e). The control device (118) is connected to the line (e)
Determine whether the sector is a good quality sector or a bad sector using the signal from the controller and the contents of the sector address being detected at that time, and store it in the memory of the control device (118). . 2, the presence or absence of a bad sector is determined over one track or multiple tracks.

The envelope detection circuit (115) inputs and rectifies the output of the preamplifier (11) in the section where a signal of /1 level is supplied to the line (c) (that is, the information recording area), and calculates the Check if a recorded signal is present. If a recorded signal exists, it is transmitted to the controller (118) over the line (0).The controller (118) uses this signal and the contents of the sector address being detected at the time to determine whether the signal is recorded or not. The sector is stored in the memory as a write-inhibited sector in which no signal can be recorded.This inspection is performed every track or every plural tracks, or over an area corresponding to the length of the signal to be recorded next.

The digital/L/demodulation circuit (116) is used only when reproducing the recorded signal, and reproduces the modulated signal recorded on the optical disk, demodulates it using a known clock reproduction technique, and converts it into digital data. is supplied to line Q as The error correction circuit (117) corrects errors in the data according to a predetermined algorithm, makes one pile of lines (■) as correct data, and transmits the data to the control device (118). Control device (IIs) Consists of a microprocessor, etc., and controls the entire system of the optical recording/reproducing device shown in Figure 2, search control to search for a desired 1-rack, signal recording, playback-related control, and sector management. etc., are recorded.

When all the signals have been recorded on the track at address N in the above manner, the light beam moves to the next N+1''41f track, performs the preliminary check of each sector as described above, and continues recording the same signals as described above.

FIG. 4 is a block diagram of an embodiment of the dropout detection circuit (113). The reproduced signal B, which is the output of the preamplifier (11), is amplified by the amplifier (I2) and then passed through the first compressor circuit (13) and the inverting amplifier (15) with a gain of 1 to the second compressor circuit (16). ).The clamp outputs C and D clamped by the respective clamp circuits (Ia
It is binarized with the threshold voltage G of the threshold voltage generation circuit (18) at η. The mepurious signal generated in the clamp circuit (+311 (16) is removed by the first Kufnop (the binary output E of Ia and the binary output 0 to the second quanpu θ are the clamp compensation circuit 09 shown in Figure 8). It is input as a signal H to the dropout counting circuit (21), and is input to the clock generation circuit (21).
4. Cumulatively add the length and number of piston outs by the clock pulse K generated at α. do. Dropout counting circuit (2
The output J of 1) is taken into the control device @ (118) in FIG. 3, and it is determined whether it is a bad sector or not.

FIG. 5 is a waveform diagram of each part of FIG. 4. The reproduced signal B is generated as shown in FIG. 5 (1) as a result of the DC signal components included in the track address area, sector address area, and recorded sector signals being lost due to the frequency band of the preamplifier (11). It causes a lot of trouble. This is why a clamp circuit is required to remove this bulge. The reproduced signal B has a dropout (L) in which the signal amplitude decreases and a dropout (M) in which the signal amplitude increases.

The clamp circuit (13) θ0 is composed of a capacitor (to), a diode, and a resistor (3) as shown in FIG.

FIG. 7 shows the waveform of the clamp output with respect to the clamp input applied to the clamp circuit of FIG. Figure 7 (+)
When a non-conducting input is applied to the diode (24) as shown in (II), the input is almost exactly clamped to 0''v.On the other hand, as shown in FIG. When an input with the polarity in the conduction direction is applied, the diode → turns on during the pulse reflex width Ta and fills the capacitor (to), and the peak voltage v1 of the input is generated at its terminal, and the input pulse becomes 0''. A false voltage waveform shown on the axis of FIG. 7 is generated at the moment when the voltage reaches v. This voltage waveform takes the form of a discharge at a constant T when the capacitance of the capacitor (to) is multiplied by the resistance value of the resistor 022. This is more than 910 times larger than the time constant τ, which is the product of the forward resistance of the diode and the capacitance of the capacitor.

Dropout occurs at (11) to (V) in FIG.

M is a false voltage waveform L2.M similar to that shown in FIG. 7 except that the polarity is different. M2 occurs. Ll and Ml are the target clamp output waveforms. Therefore, Fig. 5 (II) (I
Figure 5 (iV (Vl
As shown in the figure, the binarized output of the target dropout L3.
M3 and false binarized output L4. M4 is generated and becomes entrenched.

Moreover, the time constant iT of the clamp circuit (1310φ) must be selected one order of magnitude higher than the dropout time width Td as shown in Fig. 7 (
11) Since the peak of the pulse of the clamp output C becomes large, it is not possible to reduce at and b, and this -! Until then, the result is a false pulse that is much longer than the true dropout width, making detection of the dropout width and length very inaccurate. Clamp compensation circuit 0!
J) is the false 'i' generated by the above-mentioned clamp circuit θ
This circuit detects the t-pressure and false pulses and reproduces the accurate dropout valve width, and the circuit is shown in FIG.

In Figure 8, (2m e26+ (271(c)
is an inverter, 400) is a shift register (for example, T
i company 5N74LS164), Suzu 0 (3rA is a D type latch (for example, Ti company 5N74LS74), (g) (
Goods) (3 yen +, n (371 is 2-person NAND% (to)
(39) is a two-person cover D.

FIG. 9 is a timing chart of signals of each part in FIG. 8. Symbols common to FIGS. 4 and 5 and FIGS. 8 and 9 are the same signals.

The binarized output E of the clamp f+3 is connected to the inverter (2 [it
The signal is inverted by the shift register 4 and the clock generator circuit 0
) is captured at the timing of clock I. On the other hand, the clamp (binary output F) is similarly inverted by the inverter (to) and taken into the shift register at the timing of the clock I.The QA terminal output of the shift register (after being inverted by the inverter (27+), Type latch (input to D terminal of 311, shift register (3υ Qc terminal output O)
It is latched at the rising edge of the trailing edge. This D type latch (
The output R of the clamp (13) indicates the false bus existence period of the binary output E of the clamp (13), and is reset by the rising edge pulse P of the binary output E of the clamp (13). P is created by the shift outputs of the QA and QB terminals of shift register 4, the inverter η, and NAND.

On the other hand, the QA terminal output of the shift register (30) due to the binarized output F of the compressor 0Q is inverted by the inverter ρυ, and then
D type latch (6D type latch input to 3 D terminals and latched at the rising edge of shift output N of Qc terminal of shift register (29) (output S of 32 is clamped H)
It shows the false parnu output Jυ' of the binarized output F,
It is reset at the rising edge of the binarized output F of the clamp 0. The rising edge pulse Q is generated by a shift register (the shift output of the QA and QB terminals, an inverter @, and a NAND).

The shift outputs of the QA, QB, and QC terminals of the shift register (2 branches) correspond to the 1st, 2nd, and 3rd stages in terms of the number of shift stages, and each output is separated from each other by the period of clock I. It has been delayed.

The false pulses are the binarized outputs E and D of clamp 0 (8).
This occurs when both the outputs ゛R of type latch (Mi1) are 1', or when the binary output F of clamp 0 (2) and the output S of D type latch θ are both N1''.Here, 2 The output of the first stage output terminal QA of shift register Shikoku is used instead of the value outputs E and F, but there is no essential difference except that there is a difference between one buffless station of clock ■.Shift register e29 ) (3o) 3rd stage output terminal. C's output N, 0 is the clamp circuit (1 weight and comparator (+41
(Considering the difference in time delay between Although the decomposition time, dot, and tube out length of the clock I include an error of two pulses, the accuracy of detecting false pulses is much higher.Clamp (binarization of 131) Output E and clamp (1
The binary output F of 61 is NAND (331 tare JO, t
The false pulse detection signal T is added to AND (391) with the false pulse detection signal T to obtain the clamp compensation dropout output U.The false pulse detection signal T is the inverted output of the first stage output terminal QA of the shift register 4. NAND with the output R of the D type latch (31) (3G! AND(
(to) AND l, and IILll indicates false vane detection.

As is clear from the above explanation, the clamp compensation circuit shown in FIG. In a clamp circuit that becomes a lamp input, the moment the clamp input ends and the clamp diode turns off, the voltage that has been charged in the clamp capacitor until then is output to the clamp output.
Although a large false voltage is generated, the clamp output that is subsequently output is exposed at the trailing edge of either the positive polarity clamp circuit output or the negative polarity clamp circuit output, and is operated in such a way as to not kill it.

Effects of the Invention According to the Josui invention, recorded sectors and unrecorded sectors are preserved in any track, causing a large dip in the reproduced signal, and furthermore, playback due to uneven reflectance of the optical disc. The clamp circuit absorbs the i-plate width fluctuation of the signal and enables good dropout pulse detection.

Furthermore, the present invention is applicable to cases in which the dropout increases the output level of the reproduced signal (for example, the reflected light intensity increases depending on the recording material of the optical disk, the groove shape of the guide track, etc.), and those in which the output level decreases. (for example, pinholes, dust, etc.), it is possible to detect the false clamp output resulting from clamping with the clamp circuit, provide a circuit to compensate for this, and detect the exact number and length of dropouts. This is what makes it possible.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the format of an optical recording disk that can be recorded and played back, FIG. 2 is a block diagram showing an example of an optical recording and playing device, and FIG. 3 is a block diagram showing an example of the structure of a playback signal processing circuit. 4 is a block diagram showing an example of the configuration of a dropout detection circuit, FIG. 5 is a signal waveform diagram of each part of FIG. 4, FIG. 6 is a circuit diagram showing an example of the configuration of a clamp circuit, and FIG. FIG. 8 is a block diagram showing a configuration example of the clamp compensation circuit, and FIG. 9 is a timing chart of signals of each part in FIG. 8. (1)...Light source, (8)...Optical recording disk, θ3
(+61...first and second clamp circuits, (14
1 (lη...first and second control t<Ly=evening,
0 Yang...Threshold voltage generation circuit, 09)...Clamp compensation circuit, (20)...Clock generation circuit, I1)...
・Dropout counting circuit, 4 (g)...Shift register, H (3Z -= D type latch, (tl)
(t,)-(tm)...information recording area, (n,)(
n, )...(nm)...Sector address area agent
Yoshihiro Morimoto Figure 1 Figure 2 Figure 3 197- Vinegar) Sui Nobin Figure 5 Figure 2 Figure 7 Ann Figure β 3 198- Figure 2

Claims (1)

[Claims] L means for focusing a laser beam into a minute diameter and irradiating it onto an optical recording disk; means for recording and reproducing a signal using the irradiated light on the optical recording disk having a track address area, a sector address area, and an information recording area; and recording the signal. In the apparatus, the apparatus has means for inspecting dropout of the information recording area in which the signal is recorded from the reproduced signal of the Dinuku immediately before recording, and records by skipping sectors determined to be bad sectors according to the inspection result, It has a first clamp circuit that clamps the reproduced signal, and a second clamp circuit having a polarity opposite to that of the first clamp circuit, and the output of the second clamp circuit is set to 2 at a predetermined threshold voltage. Optical information recording/reproducing device 2, characterized in that dropout of the information recording area is detected by means for converting into a value and means for counting the time width of the binarized output.First clamp circuit. The first binarized output of the output and the second output of the second clamp circuit
After being delayed, the binary outputs of the first two
An overlap between the recovery edge of the delayed output of the digitized output and the binarized output, and an overlapped edge of the trailing edge of the delayed output of the second binarized output of the first binarized output are detected; 1st. Claim 1: The second clamp circuit is configured to suppress a false output caused by discharge of the clamp capacitor at the trailing edge of the dropout that occurs in the conduction direction of the clamp element of the second clamp circuit. The optical information recording/reproducing device described above.